1. Field of the Invention
This invention relates to a scroll fluid apparatus handling a compressible fluid that can be utilized as compressors including compressors of air conditioning systems, refrigerating apparatus, freezing apparatus, etc. and compressors for raising the air pressure, vacuum pumps and expanders for generating a rotary motive force.
2. Description of the Prior Art
A substantial number of patents have been issued on scroll fluid apparatus including, for example, U.S. Pat. Nos. 801,182 to Creux, 3,802,809 to Vulliez, 3,884,599 to Young et al, 4,082,484 and 4,129,405 to McCullough, and 4,160,629 to Hidden et al.
Of all these patents, only Hidden et al. and McCullough ('405) are directed to an inlet port and an outlet port for a fluid handled by the scroll fluid apparatus.
Hidden et al. and McCullough both relate to a liquid pump and comprise inlet and outlet ports and liquid transfer passage means maintained in communication with these ports, so as to discharge a stream of fluid free from pulsations quietly, at a considerably high speed and with a high degree of efficiency.
Young et al. ('599) shows a high pressure port of circular shape, which is located in such a manner that a part of the circle defining the port is substantially coincides with a part of the outer side wall curve of the wrap of the orbiting scroll member at the moment just before the moment when the sealed compression pockets are in communication with the center pocket. It should be noted, however, that Young et al. does not disclose the actual profile of the port. In addition, if the high pressure port illustrated in the drawings of Young et al. is assumed to be the actual profile, the port is not satisfactory because sufficient seal would not be maintained between the port and the sealed compression pocket defined by the outer side wall of the orbiting wrap and the inner side wall of the stationary wrap. More specifically, since the relative movement between the end face of the orbiting wrap and the opposing surface of the stationary end plate is small, and the distance between the port and the sealed pocket is very small at the end of compression stroke, effective sealing of the gap between the end face of the wrap and the opposing surface of the end plate would not be expected so that a large amount of gas leakage from the port into the sealed compression pocket through the gap would occur.